Frequency and severity of mitral regurgitation one year after balloon mitral valvuloplasty

VALVULAR

HEART DISEASE

Frequency and Severity of Mitral Regurgitation One Year After Balloon Mitral Valvulopiasty Ju-Pin Pan, MD, Shoa-Lin Lin, MD, Jorge Uy Go, MD, Tsui-Leih Hsu, MD, Chung-Yin Chen, MD, Shih-Pu Wang, MD, Benjamin N. Chiang, MD, and Mau-Song Chang, MD

Mitral regurgitation (MR) was evaluated by Doppler echocardiography in 59 patients with mitral stenosis before, immediately after and 1 year after balloon mitral valvuloplasty (BMW. The severity of MR was graded on a scale from I+ to 4+. Echocardiographic and hemodynamic variables were analyzed to study the potential factor(s) that might predii the long-term persistence of MR. Echocardiographii variables were mitral valve thickness and motion, subvalvular change, left atrial dimension, commissural cakiition and effective balloon/mitral anular diameters. Hemodynamic variables were mitral pressure gradient, pulmonary arterial pressure, ejection fraction, mitral valve area in&x, age, gender and cardiac rhythm. Mitral valve area index increased from 0.9 f 0.5 to 1.5 f 0.8 cm*/m* immediately after BMV, and to 1.4 f 0.3 cm*/m* at l-year follow-up (p
From the Division of Cardiology, Department of Internal Medicine, National Yang Ming Medical College and Veterans General Hospital, Taipei, Taiwan, Republic of China. This study was supported in part by The National Science Council, Grant NSC 79-0412-B075-75. Manuscript received July 2, 1990; revised manuscript received and accepted September 24, 1990. Address for reprints: Ju-pin Pan, MD, Division of Cardiology, Department of Internal Medicine, Veterans General Hospital, 201 Shih-Pai Road, Section 2, Taipei, Taiwan 11217, Republic of China.

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ince the first clinical application of catheter balloon mitral valvuloplasty (BMV) by Inoue et all in 1984, it has become another alternative for the treatment of selectedpatients with rheumatic mitral stenosis. BMV is more advantageousthan surgical commissurotomy, but mitral regurgitation (MR) is an inevitable complication in some patients when the inflated balloon splits the stenosedmitral valve.2 A significant increase in MR incidence after BMV, from 8 to 13%, has been reported.3v4Pulsed Doppler echocardiography has become a useful noninvasive tool in detecting and evaluating MR and its severity.5Previous investigators used this technique to assesschangesin the severity of MR before and then 1 to 2 days after BMV.4,6 However, l-year follow-up changesin MR after BMV have never been reported. The present study was designedto observethe progressionof MR 1 year after BMV in 59 patients, to assesswhich echocardiographicor hemodynamic factor(s) might impact on predictions of the persistenceof MR after BMV.

S

METHODS Patients: From October 1987 to July 1989, we studied 59 consecutive patients with moderate-to-severe symptomatic mitral stenosis who underwent BMV. Eight patients were in New York Heart Association functional class I, 44 patients were in class II and 7 patients were in class III. Thirty-six patients had atria1 fibrillation and 23 had sinus rhythm. Three patients had had previous surgical mitral commissurotomy. Fortytwo patients underwent the single- and 17 the doubleballoon technique. Hemodynamic studies: BMV was performed in all patients via the transeptal approach with either the single or double-catheter balloon technique (Mansfield). Balloon sizeswere selectedaccording to the mitral anular diameter, which was predetermined from the average of the mitral anular diameter obtained from 3 (long-axis parasternal, 4- and 2-chamber apical) views seen on 2-dimensional echocardiograms.The effective balloon diameter in the double-balloon technique was calculated from the method proposedby Radtke et a1.7 All patients underwent right- and left-sided cardiac catheterization. Hemodynamic variables, including cardiac output and mitral pressure gradient, were measured before, immediately after and 1 year after BMV. Mitral valve area was derived from Gorlin’s formula and cardiac output was determined by the Fick method. Echocardiographic studies: All patients were studied with M-mode, 2-dimensional and pulsed Doppler

echocardiography within 3 days before, 24 hours after and 1 year after BMV, using either a Hewlett-Packard model 77020A ultrasound system equipped with a 2.5MHz phased-array transducer, or an Irex Meridian ultrasound system equipped with a 2.25-MHz phased-array transducer. MR was assessedby pulsed Doppler echocardiographicexamination in the 4- and 2-chamber apical views (Figure 1). Grading was assessedby the extent of the regurgitant jet within the left atrium during systole.5 The Doppler sample volume was swept thoroughly at various levels of the left atrium, with particular care in determining the maximal flow of the regurgitant jet. The morphologic features of mitral valve and subvalvular apparatus, including commissural calcification, mitral valve motion, mitral valve thickness and subvalvular change, were graded and scored according to our previous work.* Measurements of mitral valve motion and thickness are shown in Figure 2. Data analysis: All echocardiographic images were recorded on both strip chart paper and videotape for playback analysis. Echocardiographic measurements were performed by 2 investigators without previous knowledge of catheterization data, and the final report reflected their consensus.The left atria1 dimension was measured according to the recommendations of the American Society of Echocardiography. We used the mean value of 5 measurementsin patients with sinus rhythm and of 10 measurementsin patients with atria1 fibrillation. Mitral valve area/body surface area was defined as the mitral valve area index. The method usedto assessthe severity of MR was similar to that previously used by Abbassi et al5 (Figure 1). Statistical analysis: The Mann-Whitney rank sum test was used in all patients to compare the difference among preoperative factors with or without enhanced MR: (1) clinical and hemodynamic aspects-age, gender, mitral valve area index, mitral pressure gradient, left atria1 dimension, pulmonary arterial pressure and

FIGURE 1. Mlal regwsibtion asessed by pulsed Doppter echoeerdiographic examination in apical 4-chamber (/efl) and ?-chamber (righf) views, grading from l+ to 4+, accord& to theextentoftheregurghntjetwithintheleftatriumduring systole.AO=aor@LA=leftatrium;LV=leftventridqRA = right atrium; RV = right ventricle.

ejection fraction; and (2) morphologic features-commissural calcification, subvalvular changes,mitral valve motion and thickness. The Friedman’s analysis of variance test was used for analysis of serial changesin mitral valve area index, mitral pressuregradient and cardiac index. In addition to all these factors, cardiac rhythm, the number of balloon catheters used, effective balloon diameter/body surface area and effective balloon diameter/mitral anular diameter were examined by multiple stepwiselogistic regressionanalysis to identify potential predictors that could induce or enhance the severity of MR immediately and 1 year after BMV.

of mild valve molion. Draw a bortxonFIGURE 2. At early diistole and in long-axis paraskrnal view. Left pane/, mearumnant ~lbinetromthaedgeofanteriormitrd~tothe~of~~eorticrootwheretheclorticvahrerbat.Than6awa VarticdEnefrom~eanterofthedomeof~ankriorm~~laalletCtha~ line.Tbelenglbh7mltbetzmqohttotbe domc~theportesioraortkrootarereferradtoiuHandL,~~.TheratioofHRbthe~of~mibdvalve The ratio of AMVT/AOT is mitral valve Wdmess. AMVT = thkkmotion. Right pm&, ~ofmitralvalvetkkness. ness of anterior nitrai IeafteQ AOT = thickness of postehr wali of aortlc root; other abbreviations as in Figue 1.

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All results are expressedas mean f standard deviation. A value <0.05 was consideredstatistically significant. RESULTS Clinical hemodynamic and ehocardiographic ables: After BMV, all patients had significant

vari-

improvement in their functional class. Mitral valve area index increased from 0.9 f 0.5 to 1.5 f 0.8 cm2/m2 (p
-

regression analysis revealed that no factors, including morphologic characteristics and preoperative clinical and hemodynamicvariables, would predict the enhancement and persistenceof MR both immediately and 1 year after BMV. Mitral regurgitation: Before BMV, 45 patients (76%) had no MR; 13 patients (22%) had l+ MR and 1 patient (1.7%) had 2+ MR. Immediately after BMV, 24 patients (41%) had no MR and 6 patients (10%) remained at l+. Of the remaining patients, 27 (46%) had a different extent of increase in MR after BMV. The increase in MR severity was noted to be l+ in 23 patients (39%), 2+ in 2 patients (3.3%) and 3+ in 2 patients (3.3%). One patient, who had an increase in MR from l+ to 4+ after BMV, received a mitral valve replacement 9 months later. Compared with the results immediately after BMV, 25 patients (43%) had no detectable MR at l-year follow-up, 26 patients (45%) had 1+ MR and 6 patients (10%) had a 1-grade decreasein MR, with the MR grade in 3 patients decreasingfrom 3+ to 2+, and decreasingfrom 2+ to I+ in the other 3. Only 1 patient had a further l-grade increase in MR (Figure 4). DISCUSSION Doppler echocardiography was found to be highly sensitive and specific for the detection of MR.iO According to previous reports,’ i-i4 about 9 to 20% of patients who underwent surgical mitral commissurotomy developedMR, and 8 to 20% of them had significant worsening of MR after the operation. Poor prognosis has been documented in these patients.ls BecauseBMV splits the fused commissuresof the mitral valve, MR is a potential complication of BMV. In the present study, 46% of patients had newly devel-

2.4r

c

TABLE I Variables in Patients With or Without Increase in Mitral Regurgitation After Balloon Valvuloplasty Without MR Increase Variables

(n=31)

With M R Increase (n = 28)

p Value

Clinical and Hemodynamic Age W EBD/BSA EBD/MAD EF(%) IAD (cm) MPG (mm Hg) PAP (mm Hg) MVI (cmz/m2)

pii-;-i

l

0 =

Od

Pre-BMV

Post-BMV

FU

flGURE 3. Se&l changes in mitral valve area index (MVI), cardiac index (Cl) and mitral pressure gradient (MPG) before bdoon mitral vahdoplasty (prwBMV), immediately after (post-BMV) and al l-year follow-up (PU). *p <0.05; **p


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43fll 18*2 0.9 f 0.1 45*9 5.1 f0.7 12f7 54f23 0.9 f 0.3

42f16 18f2

NS NS

0.9fO.l

NS NS

42f 12 5.1 iO.8 12ill 53i23 0.8 f 0.2

NS

NS NS NS

Morphologic CC grade MVM grade MVM score MVT grade MVT score SVC grade

1.4f0.8 0.4fO.l 0.8 f 0.7 1.8f0.8 0.8 f 0.7 0.9 f 0.8

1.6f0.6 0.4fO.l 0.8 & 0.7 1.7kO.9 0.8 f 0.7 1.4f0.7

NS

NS NS NS NS -co.05

CC = commissural calafication; EBD/BSA = effective balloon diameter/body surface area: EBD/MAD = effective balloon diameter/mitral anular diameter; EF = ejection fraction; LAD = left atrIal dimension; MPG = mitral pressure gradlent; MVI = mitral valve area index; MVM = mitral valve motion; MVT = mitral valve thlckness; NS = not significant; PAP = pulmonary artery pressure; SVC = subvalvular change.

oped or increased MR immediately after BMV, in accordance with previous reports (32 to 46%).4,6J6This study shows that MR is not a major problem after BMV. Our results reveal that, immediately after BMV, only 4 of 59 patients (7%) had an increase in MR of >2+. Patients with severe MR (L3+) presentedwith splitting or commissures instead of with fracture of valve leaflets or tearing of chordae tendineae. Only 1 patient (1.7%) required valve replacement becauseof a fracture of the ring anulus by an oversizedballoon. Surprisingly, there were 2 patients-l with 2+ and another with 1+ MR before BMV-who achieveda l-grade reduction of MR. The reason for the decreasein MR severity after BMV might be a relatively better coaptation of the unsmooth margin of the diseasedvalve leaflet, separatedby the catheter balloon. At l-year follow-up, 6 patients (22%) with worsened MR immediately after BMV had a l-grade decreasein MR. The slight decreasein mitral valve area and the increase in pressure gradient (Figure 3) from immediately to 1 year after BMV suggeststhat there was a refusion of the split commissuresof the mitral valve, which might contribute to the decreasein the extent of MR. Unlike previous grading and scoring systems,4J7different criteria were used to evaluate the morphologic characteristics of the mitral valve in this study. First, we measured the ratio of thickness between the anterior mitral leaflet and the posterior wall of the aortic root to assessthe mitral valve thickness as a factor to negate the effect of gain control. Second, we measured the slope of the diastolic doming of the anterior mitral leaflet to reflect the severity of commissural adhesion and the pliability of mitral valve motion. The echocardiographic score of valvular or subvalvular morphologic abnormalities did not distinguish between patients with or without an increasein MR immediately after BMV.4 Chen et al6 reported that 2 variables could predict an increase in MR: (1) the ratio of the sum of 2 balloons and the mitral anulus diameter, and (2) the severity of

subvalvular change. However, multiple stepwiselogistic regression analysis in this study revealed that an increasein MR could not be predicted from any clinical or hemodynamicvariables and morphologic characteristics of the mitral valve. The grading of the severity of MR by pulsed Doppler echocardiography correlated well with the findings of left ventriculography in our laboratory in a seriesof 108 patient@ (K value = 0.77), which was as good as the report of Pons-Llado et a1.19The interobserver reproducibility in the quantitation of the extent of MR has been quite good (K value = 0.85) in our previous work.‘* In conclusion, MR is a complication frequently seen after BMV. Only a small number of patients (6.7%) had severeMR (13+) in our study. No clinical or morphologic variables can predict the developmentof significant MR after BMV in these patients. Moreover, at lyear follow-up, somepatients may even have decreased severity of MR by Doppler echocardiography. Therefore, it is suggestedthat MR is not a major problem in patients undergoing BMV. However, becauseour patients comprised a small population, further large-scale observationsand long-term follow-up in patients who do have MR after BMV may be warranted. Study limitations: During pulsed Doppler examination, the sampling sites were carefully and progressively moved through various levels in the left atrium. Nevertheless, estimation of the severity of regurgitation by pulsed Doppler echocardiography is a semiquantitative method*O;the accuracy of regurgitant jet mapping will be affected by several factors: (1) left atria1 size and compliance, (2) left ventricular pressureand contractility, (3) the direction of the jet flow, and (4) the character of different machine and transducer settings. Overestimation of MR may occur in patients with a normal or hyperdynamic heart, and normal size of the left atrium with central jet flow. Underestimation may occur in patients with either 1 of left ventricular dysfunction, dilated left atrium, eccentric jet or with a combination of

.

FIGURE 4. Sedd changes in mitral regurllldhwdpatlentsbofaro zmy cdvllkphrty m-BMW, immdatoly aftor (post-RMV) and at lyoar follow-up (N). Grathg rangod from Oto4+.Nwnbews&owlinesauenunbe!rsofpathts.*Patientrecebdpros-

I

Pre-BMV (n=59)

Post-BMV (n=59)

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these factors. We found that either overestimation or underestimation in mapping the severity of MR is frequently seen in caseswith grading <2+ and eccentric jet.18 The application of color Doppler echocardiography may assistto someextent in clarifying theselimitations.*’

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